Methods and apparatus for performing discectomy

ABSTRACT

Methods and apparatus for performing a discectomy are disclosed herein. In some embodiments, a surgical tool for use in a therapeutic treatment of a patient includes a handle; an upper arm coupled to the handle; a lower arm coupled to the handle; a pivot arm coupled to one of the upper arm or the lower arm via a first pivot pin; and an end effector pivotably coupled to the pivot arm via a second pivot pin, wherein actuation of the handle causes movement of the pivot arm and articulation of the end effector.

FIELD OF THE INVENTION

The invention relates to methods and apparatus for performing adiscectomy.

BACKGROUND OF THE INVENTION

Bones and bony structures are susceptible to a variety of weaknessesthat can affect their ability to provide support and structure.Weaknesses in bony structures have numerous potential causes, includingdegenerative diseases, tumors, fractures, and dislocations. Advances inmedicine and engineering have provided doctors with a plurality ofdevices and techniques for alleviating or curing these weaknesses.

In some cases, the spinal column requires additional support in order toaddress such weaknesses. One technique for providing support is toextend a structure between adjacent bones, the structure connected ateach end to a polyaxial screw “tulip”, or yoke, connected to a bonescrew inserted within the bone.

Preparation of the intervertebral disc space includes maneuvering acutting tool within a small space. Access to the disc space may belimited, as well, for example when conducting a minimally invasiveprocedure. The foregoing and other diseases often require the removal orshaping of body tissue through a minimal incision, for example in alaparoscopic procedure, where the tool must be sufficiently small topass through a small opening in the body.

It is desirable to separate the nucleus from the annulus within theintervertebral disc space while also bring able to fit the disc preptool through a small diameter cannula extending through the incision.Removal of tissue from the endplates of the vertebrae adjacent the discspace can be accomplished with various instruments. However, it isdifficult to cut vertically through the disc so as to separate thedegenerated nucleus from the annular tissue. It is also necessary toensure that the annulus furthest away from the incision (e.g.,contralateral in a lateral procedure) is not cut. It is also necessaryto address the varying levels of curvature that different patients havewhen removing cartilaginous tissue from the endplates.

SUMMARY OF THE INVENTION

Embodiments of methods and apparatus for performing a discectomy aredisclosed herein. In some embodiments, a surgical tool for use in atherapeutic treatment of a patient includes a handle; an upper armcoupled to the handle; a lower arm coupled to the handle; a pivot armcoupled to one of the upper arm or the lower arm via a first pivot pin;and an end effector pivotably coupled to the pivot arm via a secondpivot pin, wherein actuation of the handle causes movement of the pivotarm and articulation of the end effector.

In some embodiments, a surgical tool for use in a therapeutic treatmentof a patient, includes a handle extending from a proximal end to adistal end. an upper arm coupled to the handle; a lower arm coupled tothe handle; a pivot arm coupled to one of the upper arm or the lower armvia a first pivot pin; and an end effector pivotably coupled to thepivot arm via a second pivot pin, wherein actuation of the handle causesmovement of the pivot arm and articulation of the end effector. Thehandle includes a body having a central channel extending from a distalend to a point between the proximal end and the distal end; a carrierdisposed around the body and having external threads; a knob surroundingthe body and carrier, the knob having internal threads corresponding tothe external threads of the carrier, wherein rotation of the knob causeslinear translation of the carrier along an axis of the handle; anattachment arm disposed within the central channel and coupled to thecarrier via a pin, wherein the attachment arm configured to mate with acorresponding feature of the surgical tool.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete understanding of the present invention, and theattendant advantages and features thereof, will be more readilyunderstood by reference to the following detailed description whenconsidered in conjunction with the accompanying drawings wherein:

FIG. 1 depicts a discectomy instrument in a retracted position inaccordance with embodiments of the present disclosure;

FIG. 2 depicts the discectomy instrument of FIG. 1 in an extendedposition;

FIGS. 3A-3C depict an articulating end of a discectomy tool inaccordance with embodiments of the present disclosure;

FIGS. 4A-4B depict cross-sectional views of the articulating endeffector of a discectomy tool in accordance with embodiments of thepresent disclosure;

FIGS. 5A-5E depict an adjustable stop for use with a discectomy tool inaccordance with embodiments of the present disclosure;

FIGS. 6A-6B depict an articulating end of a discectomy tool inaccordance with embodiments of the present disclosure;

FIGS. 7A-7C depict cross-sectional views of the articulating endeffector of a discectomy tool in accordance with embodiments of thepresent disclosure;

FIGS. 8A-8B depict close-up views of an articulating end effector of adiscectomy tool in accordance with embodiments of the presentdisclosure;

FIGS. 9A-9B depict an articulating end effector of a discectomy tool inaccordance with embodiments of the present disclosure;

FIGS. 10A-10C depict cross-sectional views of the articulating endeffector of a discectomy tool in accordance with embodiments of thepresent disclosure;

FIGS. 11A-11C depict close-up views of an articulating end effector of adiscectomy tool in accordance with embodiments of the presentdisclosure;

FIGS. 12A-12D depict a removable handle for use with a discectomy toolin accordance with embodiments of the present disclosure;

FIGS. 13A-13C depict an indicator disposed on the removable handle ofFIGS. 12A-12D in accordance with embodiments of the present disclosure;

FIGS. 14A-14C depicts cross-sectional views of the removable handle ofFIGS. 12A-12D at different positions of the articulating portion;

FIG. 15 depicts an isometric view of an adjustable stop in accordancewith embodiments of the present disclosure;

FIGS. 16A-16B depict the adjustable stop of FIG. 15 coupled to adiscectomy tool in accordance with embodiments of the presentdisclosure;

FIGS. 17A-17B depict cross-sectional views of the adjustable stop ofFIG. 15;

FIGS. 18A-18B depict cross-sectional views of the adjustable stop ofFIG. 15; and

FIG. 19 depicts a k-wire in accordance with embodiments of the presentdisclosure.

DETAILED DESCRIPTION OF THE INVENTION

With reference to FIGS. 1 and 2, a surgical instrument, or tool 100 inaccordance with some embodiments of the present disclosure will bedescribed. In some embodiments, the tool 100 includes an articulatingend effector 102, in this embodiment a ring curette for cutting tissue.For example, tool 100 may be used to prepare vertebral endplates, or anintervertebral space, for insertion of a stabilizing implant. Tool 100enables a large angle of articulation of end effector 102, which canhave various shapes, as will be discussed below. Moreover, tool 100 maybe used to articulate one or more of any type of device, including butnot limited to the examples of cutter, curette, pincher, grasper, lightsource, dilator, clamp, hose, retractor, sensor, other articulatingtool, or optical device. Tool 100 further advantageously includes anextension 104, a handle 106 connected to extension 104, a moveabletrigger 108, and a trigger bias 110 operative to return trigger 108 to astarting position after actuation.

While a surgical instrument particularly benefits from the disclosure,it should be understood that any tool requiring a wide range of motion,insertable through a small opening, may be fabricated in accordance withthe disclosure. This may include, for example, mechanical repair orassembly tools.

Extension 104 includes an upper arm 112 and a lower arm 114 which aremutually connected whereby lower arm 114 is affixed to handle 106, andupper arm 112 is caused to slide relative to lower arm 114 as trigger108 is actuated or operated. Lower arm 114 and upper arm 112 may beconnected by any known means, including a dovetail or other mutuallyinterlocking configuration, or lower arm 114 may form an enclosure orsleeve containing upper arm 112.

In accordance with the disclosure, upper arm 112 and lower arm 114 areelongated and narrow, such that they may form a laparoscopic instrumentpassable into the body of a patient through a cannula extending throughminimally invasive incision, for example though a stab type incisionwhich may be less than 30 mm in length, for example about 15 mm inlength, but may be larger as deemed therapeutically best by the medicalpractitioner. Typically, such instruments form a total width of lessthan 15 mm, and in most cases substantially less than 15 mm, for exampleabout 6 mm or less. The upper arm 112 extends from a proximal end to adistal end. The distal end of the upper arm includes a channel 118,through which a distal end of the lower arm 114 passes.

FIGS. 3A-3C depict side views of the tool 100 in an initial position,intermediary position, and fully extended position of the end effector102, respectively. FIGS. 4A and 4B depict cross-sectional views of thetool 100 in the initial and fully extended positions, respectively. Withreference to FIGS. 3A-3C and 4A-4B, end effector 102 operates on anactive pivoting mechanism which includes a first pivot pin 116A, asecond pivot pin 116B, and a third pivot pin 116C. The first pivot pin116A is fixed to the distal end of the lower arm 114 and a proximal endof a pivot arm 117. The first pivot pin is configured to translate alongthe channel 118. The second pivot pin 116B is fixed to the end effector102 and a distal end of the pivot arm 117, thus allowing the secondpivot pin 116B to move about the third pivot pin 116C, as discussedbelow. The third pivot pin 116C is fixed to a distal tip 119 of theupper arm 112 and to the end effector 102, thus allowing the endeffector 102 to rotate about a pivot axis passing through the thirdpivot pin 116C. As a result, when the trigger 108 is actuated, the lowerarm 114 translates relative to the upper arm 112, moving the lower arm114 forward. This forward movement of the lower arm 114 pushes thesecond pivot pin 116B beyond the first pivot pin 116A (as shown in FIGS.3C and 4B) because of the curvature of the pivot arm 117. The movementof the second pivot pin 116B beyond the first pivot pin 116Aadvantageously provides a sweep angle of about 160°. Such a large sweepadvantageously provides an improved ability to separate the nucleus ofthe disc from the annulus and allows for the insertion of the tooleither in the initial position or in the fully extended position. Thegeometry of the end effector 102 (i.e., the opening in the ring curette)advantageously allows a portion of the pivot arm 117 to be disposedwithin the end effector 102 in the initial position, thus maintaining alow profile of the tool 100 during insertion.

In some instances, however, great care must be exercised not to cutthrough the annulus of the disc on the side of the disc space oppositeinsertion of the tool. In such instances, the surgeon may wish to limitthe amount of travel of the end effector of the tool to a predeterminedamount of travel. Typically, instruments are marked with lengthindicators and it is up to the surgeon to determine how far into thedisc space the tool has been inserted or how far beyond a distal end ofa cannula the tool extends based on these markings. As such, theinventors have developed an adjustable stop 500 configured to limit theamount of travel of the end effector of a surgical tool. The travelallowance can be adjusted within a range defined by the surgeon at thebeginning of the surgery. However, the surgeon may also change thattravel allowance mid-surgery, if necessary.

FIGS. 5A-5E depict an adjustable stop 500 for use with a surgical tool(e.g., tool 100 described above) to limit the amount of travel of theend effector of the tool into the disc space. The adjustable stop 500 iscoupled to a cannula 502 through which the tool is inserted into thedisc space. Each tool includes a hard stop 504 (e.g., a collar orshoulder) that typically limits the amount of travel of the tool throughthe cannula 502. The adjustable stop 500 is moved to a desired positionalong the cannula 502 such that when the hard stop 504 contacts theadjustable stop 500, the tool cannot be advanced further into thecannula 502. As a result, the distance traveled by the end effector ofthe tool beyond a distal end 506 of the cannula 502 is limited to adesired distance. FIG. 5A depicts the adjustable stop 500 positioned atthe lowest position along a proximal portion of the cannula 502. Thetool protrudes beyond the distal end 506 of the cannula 502 a distance Aat this stop position. FIG. 5B depicts the adjustable stop 500 positionat the highest setting along the proximal portion of the cannula 502.The tool protrudes beyond the distal end 506 of the cannula a distanceB, which is less than the distance A, at this position.

In some embodiments, the position of the adjustable stop 500 isadjustable using interacting features on the proximal portion of thecannula 502. In such an embodiment, the adjustable stop 500 includes aninternal body 508 that includes a first set of teeth 510 that mate witha second set of teeth 512 on the cannula 502. When the first and secondsets of teeth 510, 512 are engaged, the adjustable stop 500 is preventedfrom moving along the cannula 502. When the teeth are disengaged, theposition of the adjustable stop 500 may be adjusted. To engage anddisengage the teeth, the internal body is rotated such that the firstset of teeth 510 are rotated out of engagement with the second set ofteeth 512. In some embodiments, to rotate the first set of teeth 510 outof engagement, a collar 514 of the adjustable 500 may be pulled back(i.e., proximally). The collar 514 includes a radially inward extendingpin 516 that extends through a linear slot 518 formed in an outerhousing 520 and a helical slot 522 formed in the internal body 508. FIG.5D depicts the adjustable stop 500 with the outer housing 520. FIG. 5Edepicts the adjustable stop 500 without the outer housing 520. As thecollar 514 is pulled back, its motion is constrained by pin 516 in thelinear slot 518 and the internal body 508 is caused to rotate due to themotion of the pin 516 along the helical slot 522. As depicted in FIG.5C, an internal spring 524 is disposed between the outer housing 520 andthe internal body 508 to bias the collar 514 distally (i.e., towards aposition in which the first and second sets of teeth 510, 512 are inengagement).

Referring now to FIGS. 6A-8B, an end effector 602 of surgical tool 600in accordance with some embodiments of the present disclosure will bedescribed. As depicted in these figures, the end effector of the tool600 may be a cup curette. Because the tool 600 is substantially similarto the tool 100 described above, only a distal portion of the tool 600is depicted in these figures and described below. FIGS. 6A and 7A depictthe distal end of the tool 600 in an initial position (i.e., insertionposition) and FIGS. 6B and 7C depict the distal end of the tool 600 in afinal position (i.e., fully extended position). FIG. 7B depicts thedistal end of the tool 600 in an intermediate position.

The tool 600 is configured to be inserted into the disc space in theinitial position (FIGS. 6A and 7A), and then articulated once inside.The articulation is controlled using a handle similar to the handle 106discussed above. The articulation of the end effector 602 functions asan active pivot based on a two pin mechanism. A first pivot pin 616A isfixed to the end effector 602 and a lower arm 614 of the tool. A secondpivot pin 616B is fixed only to the end effector 602, thus allowing thesecond pivot pin 616B to translate within an upper arm 612 of the tool600. As the handle is actuated, the upper arm 612 translates forward(i.e., distally) relative to the lower arm 614. Because the second pivotpin 616B is not fixed to the upper arm 612, but instead allowed totranslate, the end effector 602 begins to rotate about the first pivotpin 616A. The actuation continues until the upper arm 612 reaches aphysical stop. The physical stop can either be accomplished by a slot618 into which the second pivot pin 616B extends, or by some limitationon the handle used to actuate the tool 600.

In some embodiments, the end effector 602 also includes passivearticulation (depicted in FIGS. 8A and 8B), which is realized when theend effector 602 (i.e., the cup curette head) contacts an endplateadjacent to the disc space. Once contact occurs, the end effector 602will remain aligned with the endplate as long as pressure is maintained.The entire tool 600 can then be pulled back and forth, as a standard cupcurette, to remove tissue from the endplates. To achieve such passivearticulation, the end effector 602 includes a third pivot point 616Ccoupling a head 620 of the end effector 602 to a pivot arm 617. The endeffector 602 is allowed to pivot about the third pivot point 616C.

The inventor has discovered that the active pivot of the tool 600 isadvantageous because it does not suffer from the drawbacks associatedwith a tool having two fixed pivot pins, one that is translated and theother that is rotated about. The translating pin in such a device isalways at a constant distance from the rotation pin, thus creating aradius. The passive pivot of the tool 600 advantageously accommodatesthe different endplate shapes of different patients. In contrast, astandard cup curette suffers from point loading, which can result inover-stress at a specific area of bone, potentially breaking through theendplate.

Referring now to FIGS. 9A-11C, an end effector 902 of surgical tool 900in accordance with some embodiments of the present disclosure will bedescribed. As depicted in these figures, the end effector of the tool900 may be a rake. Because the tool 900 is substantially similar to thetool 100 described above, only a distal portion of the tool 900 isdepicted in these figures and described below. FIGS. 9A and 10A depictthe distal end of the tool 900 in an initial position (i.e., insertionposition) and FIGS. 9B and 10C depict the distal end of the tool 900 ina final position (i.e., fully extended position). FIG. 10B depicts thedistal end of the tool 900 in an intermediate position.

Similar to the tool 600, the tool 900 is configured to be inserted intothe disc space in the initial position (FIGS. 9A and 10A), and thenarticulated once inside. The articulation is controlled using a handlesimilar to the handle 106 discussed above. The articulation of the endeffector 902 functions as an active pivot based on a two pin mechanismsimilar to the one discussed above with respect to the tool 600. A firstpivot pin 916A is fixed to the end effector 902 and a lower arm 914 ofthe tool. A second pivot pin 916B is fixed only to the end effector 902,thus allowing the second pivot pin 916B to translate within an upper arm912 of the tool 900. As the handle is actuated, the upper arm 912translates forward (i.e., distally) relative to the lower arm 914.Because the second pivot pin 916B is not fixed to the upper arm 912, butinstead allowed to translate, the end effector 902 begins to rotateabout the first pivot pin 916A. The actuation continues until the upperarm 912 reaches a physical stop. The physical stop can either beaccomplished by a slot 918 into which the second pivot pin 916B extends,or by some limitation on the handle used to actuate the tool 900.

In some embodiments, the end effector 902 also includes passivearticulation (depicted in FIGS. 11A and 11B), which is realized when theend effector 902 (i.e., the rake head) contacts an endplate adjacent tothe disc space. Once contact occurs, the end effector 902 will remainaligned with the endplate as long as pressure is maintained. The entiretool 900 can then be pulled back and forth, as a standard cup curette,to remove tissue from the endplates. To achieve such passivearticulation, the end effector 902 includes a third pivot point 916Ccoupling a head 920 of the end effector 902 to a pivot arm 917. The endeffector 902 is allowed to pivot about the third pivot pin 916C. Asshown in FIGS. 11A and 11B, the head of the end effector 902 may includean opening 930 surrounding the third pivot pin 916C to allow the head920 to pivot about the third pivot pin 916C. As shown in FIG. 11B, theopening 930 may include walls 932 to limit such pivoting by abuttingagainst the pivot arm 917. FIG. 11C depicts a top view of the head 920of the end effector 902 (i.e., the rake head).

Referring to FIGS. 12A-14C, a handle 1200 for use with a surgical tool(e.g., tool 600) in accordance with embodiments of the presentdisclosure will be described. Although reference is made to the tool 600in the following description of the handle 1200, it should be noted thatany surgical tool requiring actuation (e.g., tools 100, 900) may beutilized with the handle 1200. The handle 1200 may be a modular handlethat can be attached to multiple tools such as, for example, the toolsdescribed above. Such a handle replaces conventional handles such ashandle 106 discussed above. In some embodiments, the handle 1200 extendsfrom a proximal end 1202 to a distal end 1204 and includes a centralchannel 1206 extending from a distal end 1204 to a point between theproximal and distal ends 1202, 1204. The handle 1200 further includes anattachment arm 1208 disposed within the central channel 1206 andconfigured to mate with a corresponding feature of a tool to which thehandle 1200 is attached. In some embodiments, the attachment arm 1208includes a feature 1210 configured to receive a corresponding feature1212 of the tool to which the handle 1200 is attached. In someembodiments, the feature 1210 may be a t-shaped slot, as shown in FIGS.12A-12C. However, the feature 1210 may alternatively have any geometrycapable of attaching the handle 1200 to the tool. The attachment arm1208 is moveable along an axis 1214 of the handle 1200. As such,whichever portion of the tool the attachment arm 1208 is coupled to isalso moved back and forth with the movement of the attachment arm 1208.In some embodiments, the attachment arm is coupled to a portion of thetool that needs to be moved in order for an end effector (e.g., 602) ofthe tool to articulate (e.g., one of the upper or lower arms 612, 614).

In some embodiments, the handle 1200 includes a knob 1216 havinginternal threads (not shown) that correspond to external threads 1218 ofa carrier 1220. The carrier 1220 surrounds a body 1221 of the handle1200 and is coupled to the attachment arm 1208 via a pin 1222. As such,when the knob 1216 is rotated, the threads cause the carrier 1220 tomove back and forth along the body 1221, which in turn also causes theattachment arm 1208 to move back and forth, thus also moving the portionof the tool to which the attachment arm 1208 is attached.

As depicted in FIGS. 13A-13C, in some embodiments, the handle 1200 mayinclude an indicator 1224 configured to indicate the angular position ofthe end effector relative to the tool. In some embodiments, theindicator 1224 includes numerical values 1223 written on a proximalsurface of the body 1221 and a pointer 1229 on a proximal surface of anindicator body 1225. In such an embodiment, the pin 1222 passes througha linear slot 1226 (FIG. 14A) formed in the body 1221 and a helical slot1227 formed in the indicator body 1225 (similar to the adjustable stop500 discussed above). As a result, rotation of the knob 1216 causes thelinear movement of the carrier 1220, which causes the pin 1222 to movealong the linear slot 1226 and the helical slot 1227 as shown in FIGS.14A-14C. The movement of the pin along the helical slot 1227 causes theindicator body 1225 to rotate, thus also rotating the pointer 1229causing it to point to the correct numerical value 1223 corresponding tothe angular position of the end effector 602, as depicted in FIGS.13A-13C.

Referring to FIGS. 15-18B, an adjustable stop 1500 for use with asurgical tool (e.g., tool 100) to limit the amount of travel of the endeffector (e.g., end effector 102) of the tool into the disc space inaccordance with embodiments of the present disclosure will be described.Although reference is made to the tool 100 in the following descriptionof the adjustable stop 1500, it should be noted that any surgical toolrequiring an adjustable stop (e.g., tools 600, 900) may be utilized withthe adjustable stop 1500. The adjustable stop 1500 is coupled to acannula 1502 through which the tool is inserted into the disc space.Each tool includes a hard stop 1504 (e.g., a collar or shoulder) thattypically limits the amount of travel of the tool through the cannula1502. The adjustable stop 1500 is moved to a desired position along thecannula 1502 such that when the hard stop 1504 contacts the adjustablestop 1500, the tool cannot be advanced further into the cannula 1502. Asa result, the distance traveled by the end effector of the tool beyond adistal end 1506 of the cannula 1502 is limited to a desired distance.FIGS. 16A and 17B depict the adjustable stop 1500 positioned at thehighest position along a proximal portion of the cannula 1502. The toolprotrudes beyond the distal end 1506 of the cannula 1502 a distance A atthis stop position. FIGS. 16B and 17A depict the adjustable stop 1500position at the lowest position along the proximal portion of thecannula 1502. The tool protrudes beyond the distal end 1506 of thecannula a distance B, which is greater than the distance A, at this stopposition.

In some embodiments, the position of the adjustable stop 1500 isadjustable using interacting features on the proximal portion of thecannula 1502. In such an embodiment, the adjustable stop 1500 includes amoveable body 1508 that includes a first set of teeth 1510 that matewith a second set of teeth 1512 on the cannula 1502. When the first andsecond sets of teeth 1510, 1512 are engaged (FIG. 18A), the adjustablestop 1500 is prevented from moving along the cannula 1502. When theteeth are disengaged (FIG. 18B), the position of the adjustable stop1500 may be adjusted. To engage and disengage the teeth, the moveablebody 1508 is pressed/moved such that the first set of teeth 1510 aremoved out of engagement with the second set of teeth 1512. Theadjustable stop 1500 further includes a spring element 1529 configuredto bias the moveable body 1508 towards the engaged position (i.e., theposition in which the first and second sets of teeth 1510, 1512 areengaged).

In some embodiments, the adjustable stop 1500 further includes a tablemount 1530 configured to mount the adjustable stop 1500 to a table. Insome embodiments, the table mount 1530 extends outwardly from one sideof the adjustable stop 1500 and may include one or more openings 1532configured to receive fixation elements (not shown) to fix the positionof the adjustable stop 1500 (and anything coupled to it) with respect tothe table.

When performing an extraforaminal disc prep, surgeons need to navigatean initial trajectory through Kambin's triangle. This can be performingusing any suitable instrument (e.g., a spinal needle, a JamShidi®, ak-wire, etc.). Kambin's triangle has one leg defined by the exitingnerve root of the surgical level. If care is not taken during theinitial stab, damage to this nerve can occur. The inventor has developeda k-wire that can address this need.

FIG. 19 depicts a k-wire 1900 in accordance with embodiments of thepresent disclosure. At least a portion of the k-wire 1900 has a coating1901 formed of a polymer such as Halar®. In some embodiments, about 2-3mm of a first end 1902 of the k-wire 1900 is exposed and about 20-30 mmof a second end 1904 are exposed. The k-wire 1900 has a stainless steelcore, which is conductive and can, therefore, be used with aneuro-monitoring system. A lead (not shown) can be attached to thesecond end and stimulated. The coating 1901 allows the k-wire to beinsulated from the patient's anatomy surrounding the k-wire 1900, thusfocusing the stimulation around the nerve (i.e., at the first end 1902).As a result, an initial trajectory can be neuromonitored or stimulatedin a manner in which only the area of interest (i.e., the exiting nerveroot) is stimulated.

All references cited herein are expressly incorporated by reference intheir entirety. There are many different features to the presentinvention and it is contemplated that these features may be usedtogether or separately. Unless mention was made above to the contrary,it should be noted that all of the accompanying drawings are not toscale. Thus, the invention should not be limited to any particularcombination of features or to a particular application of the invention.Further, it should be understood that variations and modificationswithin the spirit and scope of the invention might occur to thoseskilled in the art to which the invention pertains. Accordingly, allexpedient modifications readily attainable by one versed in the art fromthe disclosure set forth herein that are within the scope and spirit ofthe present invention are to be included as further embodiments of thepresent invention.

What is claimed is:
 1. A surgical tool for use in a therapeutic treatment of a patient, comprising: a handle; an upper arm coupled to the handle, the upper arm having a distal tip; a lower arm coupled to the handle; a pivot arm coupled to one of the upper arm or the lower arm via a first pivot pin; and an end effector pivotably coupled to the pivot arm via a second pivot pin, wherein actuation of the handle causes movement of the pivot arm and articulation of the end effector from an initial position to an extended position, and wherein in the initial position the end effector is positioned adjacent to the upper arm and in the extended position extends distally beyond the distal tip of the upper arm, wherein the handle is a modular handle which extends from a proximal end to a distal end and comprises: a body having a central channel extending from the distal end to a point between the proximal end and the distal end; a carrier disposed around the body and having external threads; a knob surrounding the body and the carrier, the knob having internal threads corresponding to the external threads of the carrier, wherein rotation of the knob causes linear translation of the carrier along an axis of the handle; an attachment arm disposed within the central channel and coupled to the carrier via a pin, wherein the attachment arm has a T-shaped slot that is configured to mate with a corresponding feature of one of the upper and lower arms, wherein the handle includes an indicator configured to indicate an angular position of the end effector with respect to a rest of the surgical tool, and wherein the attachment arm is moveable along the axis of the handle.
 2. The surgical tool of claim 1, wherein the surgical tool is configured to be inserted into a vertebral disc space through a cannula.
 3. The surgical tool of claim 1, wherein the surgical tool is sized and dimensioned for laparoscopy.
 4. A system comprising the surgical tool of claim 1, further comprising: an adjustable stop configured to be coupled to a cannula through which the surgical tool is inserted into an intervertebral disc space, wherein a position of the adjustable stop along the cannula can be adjusted to limit a distance by which the end effector extends beyond a distal end of the cannula, wherein the adjustable stop includes a first set of teeth selectively engageable with a second set of teeth on the cannula to lock and unlock translation of the adjustable stop along the cannula.
 5. The surgical tool of claim 4, wherein the adjustable stop further includes a table mount configured to allow the adjustable stop to be mounted to a table.
 6. The surgical tool of claim 1, wherein the end effector is one of a ring curette, a rake, or a cup curette.
 7. The surgical tool of claim 1, wherein the end effector is a ring curette, and wherein a sweep angle of the ring curette is about 160°.
 8. A surgical tool for use in a therapeutic treatment of a patient, comprising: a handle extending from a proximal end to a distal end, the handle comprising: a body having a central channel extending from the distal end to a point between the proximal end and the distal end; a carrier disposed around the body and having external threads; a knob surrounding the body and the carrier, the knob having internal threads corresponding to the external threads of the carrier, wherein rotation of the knob causes linear translation of the carrier along an axis of the handle; an attachment arm disposed within the central channel and coupled to the carrier via a pin; an upper arm coupled to the handle; a lower arm coupled to the handle; a pivot arm coupled to one of the upper arm or the lower arm via a first pivot pin; and an end effector pivotably coupled to the pivot arm via a second pivot pin, wherein the attachment arm has a T-shaped slot that is configured to mate with a corresponding feature of one of the upper and lower arms, wherein actuation of the handle causes movement of the pivot arm and articulation of the end effector, and wherein the articulation of the end effector includes a sweep angle of 160°.
 9. The surgical tool of claim 8, wherein the surgical tool is configured to be inserted into a vertebral disc space through a cannula.
 10. The surgical tool of claim 8, wherein the surgical tool is sized and dimensioned for laparoscopy.
 11. The surgical tool of claim 8, wherein the handle is a modular handle.
 12. The surgical tool of claim 11, wherein the modular handle includes an indicator configured to indicate an angular position of the end effector with respect to a rest of the surgical tool.
 13. A system comprising the surgical tool of claim 8, further comprising: an adjustable stop configured to be coupled to a cannula through which the surgical tool is inserted into an intervertebral disc space, wherein a position of the adjustable stop along the cannula can be adjusted to limit a distance by which the end effector extends beyond a distal end of the cannula, wherein the adjustable stop includes a first set of teeth selectively engageable with a second set of teeth on the cannula to lock and unlock translation of the adjustable stop along the cannula.
 14. The surgical tool of claim 13, wherein the adjustable stop further includes a table mount configured to allow the adjustable stop to be mounted to a table.
 15. The surgical tool of claim 8, wherein the end effector is one of a ring curette, a rake, or a cup curette. 